groupaccess.c

   1 /*
   2  * Copyright (c) 2001 Kevin Steves.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  15  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  16  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  17  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  18  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  19  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  20  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  22  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  23  */
  24
  25 #include "includes.h"
  26 RCSID("$OpenBSD: groupaccess.c,v 1.6 2003/04/08 20:21:28 itojun Exp $");
  27
  28 #include "groupaccess.h"
  29 #include "xmalloc.h"
  30 #include "match.h"
  31 #include "log.h"
  32
  33 static int ngroups;
  34 static char **groups_byname;
  35
  36 /*
  37  * Initialize group access list for user with primary (base) and
  38  * supplementary groups.  Return the number of groups in the list.
  39  */
  40 int
  41 ga_init(const char *user, gid_t base)
  42 {
  43         gid_t *groups_bygid;
  44         int i, j;
  45         struct group *gr;
  46
  47         if (ngroups > 0)
  48                 ga_free();
  49
  50         ngroups = NGROUPS_MAX;
  51 #if defined(HAVE_SYSCONF) && defined(_SC_NGROUPS_MAX)
  52         ngroups = MAX(NGROUPS_MAX, sysconf(_SC_NGROUPS_MAX));
  53 #endif
  54
  55         groups_bygid = xmalloc(ngroups * sizeof(*groups_bygid));
  56         groups_byname = xmalloc(ngroups * sizeof(*groups_byname));
  57
  58         if (getgrouplist(user, base, groups_bygid, &ngroups) == -1)
  59                 logit("getgrouplist: groups list too small");
  60         for (i = 0, j = 0; i < ngroups; i++)
  61                 if ((gr = getgrgid(groups_bygid[i])) != NULL)
  62                         groups_byname[j++] = xstrdup(gr->gr_name);
  63         xfree(groups_bygid);
  64         return (ngroups = j);
  65 }
  66
  67 /*
  68  * Return 1 if one of user's groups is contained in groups.
  69  * Return 0 otherwise.  Use match_pattern() for string comparison.
  70  */
  71 int
  72 ga_match(char * const *groups, int n)
  73 {
  74         int i, j;
  75
  76         for (i = 0; i < ngroups; i++)
  77                 for (j = 0; j < n; j++)
  78                         if (match_pattern(groups_byname[i], groups[j]))
  79                                 return 1;
  80         return 0;
  81 }
  82
  83 /*
  84  * Free memory allocated for group access list.
  85  */
  86 void
  87 ga_free(void)
  88 {
  89         int i;
  90
  91         if (ngroups > 0) {
  92                 for (i = 0; i < ngroups; i++)
  93                         xfree(groups_byname[i]);
  94                 ngroups = 0;
  95                 xfree(groups_byname);
  96         }
  97 }